This invention relates generally to gas containing piping, and more particularly to a pipe coupler for sealingly connecting two sections of piping in which is disposed a gas.
Gas containing piping has been in use for many years, most notably in the transmission of such gas from one location to another. A new use of gas containing piping has, however, recently emerged. The new use of such piping is for the transmission and distribution of electrical power. Electrical utilities and manufactures are investigating the use of compressed gas insulated transmission lines for the transmission and distribution of high voltage electricity.
A compressed gas insulated transmission line typically comprises a bare electrical conductor disposed within, but electrically isolated from, a grounded pipe. An insulating gas, typically sulfur hexafluoride, is disposed within the pipe and provides electrical insulation around the centrally disposed conductor. The compressed gas insulated transmission line has many advantages; superior reliability, lower maintenance cost, greater personnel safety, and a quieter, more environmentally acceptable operation.
To provide for a transmission line, a plurality of individual pipe sections, and their corresponding conductors, are coupled together. This coupling has generally been accomplished by means of welding, thereby maintaining the pipe sealed against the escape of the compressed sulfur hexafluoride gas. Recent developments, however, may preclude the use of welds to join adjacent sections together. One such recent development is the potential feasibility of a composite, or synthetic, pipe. Instead of utilizing a solid metal pipe as the enclosure around the electrical conductor, it is possible to use fabricated, synthetic pipes. This pipe typically comprises a cylindrical core of material such as wood or pressed board, with layers of, for example, aluminum foil disposed around the inside and outside of the pipes. This synthetic pipe has distinctive advantages, such as lower cost, less weight, and superior thermal properties.
A problem has arisen, though, in the use of such synthetic pipe for transmission lines. Some means must be found to sealingly couple two sections of pipe together to form the transmission lines. The prior art method of welding cannot be utilized because of the non-weldable material. Therefore, some new means of joining such pipe sections must be found before the use of such synthetic pipe will become practical.